Train control



March 30 1926. 1,578,876

C. S. BUSHNELL TRAIN CONTROL Filed Oct. 9, 1922 2 Sheets-Shea?v 1 l 22'26 l 25 E s. [Q m ATTORNEY March 30", 1926. 1,578,876

c. s. BUSHNELL. 1

TRAIN CONTROL Filed Oct. 9, 1922 2 Sheets-Sheet 2 Patented Mar. 30,1926.

1,578,&75

"UNITED STATES PATENT 'orrica.

CHARLES S. BUSHNELL, OF ROCHESTER, NEW YORK, ASSIGNOB, TO GENERAL RAIL-WAY SIGNAL COMPANY, OF GATES, NEW YORK, A CORPORATION OF NEW YORK.

TRAIN CONTROL.

Application filed October 9, 1922. I Serial No. 598,874.

To all whom it may concern:

Be it known that I, CHARLES S. Busrr NELL, a citizen of the 'UnitedStates of America, residing at Rochester, in the connty of Monroe andState of New York, have invented certain new and useful Improvements inTrain Controls, of which the following is a specification.

This invention relates to automatic train control systems for railroads.

In safeguarding the movement of railwvay trains, it is desirable to makethe a.uto-' matic brake application or other control dependent uponcthespeed of the train, since at a given'pointthe speed of the train usu'-ally determines whether or not the train is being safely or unsafelyControlled. For example, upon approaching another train ahead andpassing a restrictive caution signal, the following train should reduceits speed; and while the following train may.

travel safely throughout the length of this caution block, its speed atthe various points in this block should be such that it may be broughtto a stop by its brakes at the end of the block. Similarly, certaintrack hazards, such as sharp curves, down grades, yard limits, and thelike, demand that the speed of the train should be restrictedirrespective B0 of the presence or absence of other trains.

ln'accordance with this invention it is proposed to make the automaticbrake application at a given point dependent upon the speed of the trainat that point in conform- 'it-y with what may be called thetime-distance interval principle, that is, the brakes are applied if thetrain takes less than a given interval of time, measured by a timeinterval device on the train, in'travelin the given 40' interval ofdistance, determined y the-spacing of trackway influence devices: Thisinventiondeals more particularly with the construction of the timeinterval device, b

7 means of which relatively short interva s 4 of time such as twoseconds, may be accu rately measured off. A further object is to providea time interval device for systems of the character described which hasa minimum number of movm and wearing parts, which has its operationdependent upon fundamental factors of mass and accelera tion, and whichis so constructed and controlled as tobe thoroughly reliable in'itsoperation, the interruption of circuits or failure of an essential partresulting in an operation on the side of safety.

In connection with the application of automatic train control torailway-s, it is considered important to retain as far as possible allof the vigilence and care that engineers now observe in controllingtheir trains, in order that the automatic train control system mayafford protection. supplementary to that already existing in theordinary o eration of railroads, instead of being a su stitute, with theresult that before an accident can result not only must the engineerfail to exercise his ordinary care, but also the train control equipmentmust fail to function.

movement afforded by the vigilance and care of the engineer, it isbelieved necessary to make provisions to encourage and substantiallyenforce such vigilance, when an automatic train control equipment isadded to the train, otherwise the engineer will be. naturally inclinedto rely upon the train control system and allow it to do his work forhim. Following out this theory, it is proposed in accordance with thisinvention to rovide' a manually operable acknowledging device which theengineer must opcrate at each trackway control point under unsafetralfic conditions, 'in order to avoidan immediate brake application,failure on the part of the engineer to make proper and timely operationof the acknowledging device resulting in the imposition of a penalty,such as, maklng it necessary for the engineer to stop the train andrestore the apparatus from the ground in order to proceed. According tothis invention, this acknowledging device is incorporated in the systemof speed control above mentioned in such a manner that the engineer, bymanipulation of the acknowledging device, can not prevent an automaticbrake application due to excessive speed.

' The, primary objects of this invention may'be said to consist in theprovision of simple, efiicient and reliable mechanism and electricalcircuits performin the functions and resultsabove describe t other withother functions essential or desira la in a speed control system of thischaracter.

Various detail purposes, objects and characteristic features of theinvention will appear hereinafter-as the description progresses.

In describing the invention in detail, reference will be made to theaccompanying drawings in which the apparatus for carryequipped withtrackway apparatus adapted to cooperate with suitable car-carriedequipment to enforce gradually decreasing speed limits of such car whenmoving in the direction of the arrow under caution trafiic conditions: r

Fig. 2 illustrates diagrammatically and partly in perspective andsection car-carried equipment adapted to enforce decreasing speed limitswhen used in connection with the trackway system shown in Fig. 1;

Fig. 3 shows a part of the balance wheel and holding or starting magnetof the time control device, and is taken on the line 3-3 of Fig. 2, asviewed in the direction of the arrow; and

Fig. 4 shows the trackway and car-carried equipment of a train controlsystem including an acknowledging device for enforcing recognition of acaution and danger signal, and speed control means for enforcingobedience to a caution signal.

In describing the invention in detail, the

system shown in Figs. 1 and 2 will first be described, this system notbeing provided with an acknowledging device, that is, a device requiringthe engineer to perform a certain act in recognition of a caution ordanger signal in order to prevent an automatic brake application, asdoes the system described in Fig. 4} The system shown in -Figs. 1 and 2merely enforces speed reduction in obedience to a caution signal, thatis compels the engineer to make apredetermined reduction in speed inorder to avoid an automatic application of the brakes.

In the embodiments of the invention illustrated, the transmission of thedesired.

of two other blocks H and J being shown. The parts and circuitsassociated with the various blocks are the same, and for conveniencewill be given like reference char.

acters with distinctive exponents. Each of the blocks is provided with atrack'battery 3 and a track relay 4, the same as in ordinary blocksignal systems. The invention is preferably used with'the usual fixedsignals; but these are well known, and I have illustrated such fixedsignals Z conventionally, without attempting to illustrate their wellknown control circuits and devices.

In each block are provided pairs of track elements T and t at theseveral points in the block at which the speed of the train is to bechecked, the spacing between the elements T and t of each pairdetermining the distance a train is permitted to run in a predeterminedtime at this point in the controlled trackway elements T and-t islocated a repeater track or line relay 8,

these relays 8 being connected in multiple between the line wire 9 and acommon return wlre C (not shown), and are energized when the track relay4 of the block in advance is energized. Since the pairs of trackelements at successive points .in the block are substantially the same,except for the spacing between these elements, they will be given thesame reference-characters with distinctive alphabetical exponents.

- The energizing circuit for the repeater track relays 8 may be tracedas follows starting from the terminal B of a suitable source of energy,wire 10, front contact 11 of the track relay 4, line wire 9,

wire'12, winding of the repeater track relay 8, wire 13 back to thecommon return .WilB C which is connected to the other side of the sourceof energy. Fromxthis it is readily apparent that, when the track relayof the block in advance is energized, all of the repeater track relays 8will likewisebe energized, thus closing their front contacts .14 andincluding the coils 7 on the back yokes of the track elements t inclosed circuits of preferably low resistance.

The car-carried apparatus of one specific embodiment of the presentinvention has been illustrated in Fig. 2. and comprises suitable deviceswhich will first be separately described. 7 One of these devicescoinprises a car element L adapted to be inductively influenced by thetrack elements T and t along the trackway. This car element L consistsof a U-shaped core 15, preferably constructed of agood grade oflaminated transformer iron, which terminates in enlarged pole pieces 16,and which is provided with a primary coil- P on one leg,

purpose for which it is intended. Although these relays have beenillustrated in the same manner, this illustration is merely conventionaland in practice the control relay GR is constructed with much smallermoving parts and controls smaller contacts than do the relays RR and SR,and will therefore function on a' smaller change of current... Theserelays have their moving parts well balanced sothat they will not beaffected by jars and vibration, and are preferably 'I'nountedin acomparatively heavy spring supported relay casing, which may be providedwith a glass panel and locked or sealed in any suitable manner. I

The car apparatus. iiiciudes a train control device K which may controlthe train in any.

suitable manner. This device K has been illustrated as anelectric-pneumatic valve, and is intended to cause an automaticapplication of the brakes, for instance, by venting the brake pipe tomake a predetermined reduction only, and simultaneously with suchventing cut off main reservoir pressure from the engineers brake.valve'so that the engineer'can not prevent the applicationcf the brakesby operating this brake valve to the release position. The particularconstruction of this train control device K does not come withinthescope of the present invention and has notbeen illustrated in detail.

Another element of the car-carried ap paratus embodying the presentinvention comprises atime control device TC. This time control-deviceemploys the fundamental factors of mass and-accelerating force tomeasure time, similar to {the well-known bal-- ance wheel .used inwatches- This time control device TC acts .to interrupt and. completecertain circuits after a fixed predetermined interval o'f-"time'afterthis device has been initiated. W

1 More specificallygithis time'control device H3. comprisesla e plate 20preferably supported in'a itar ger casing (not shown) in a directionaway from these contacts 33 shaft 24 is splined a balance or inertiawheel clearly shown in Fig. 3 of the drawings.

somewhere on the tender, or at any other suitable place on thelocomotive or tender, or on an electrically propelled vehicle. On top ofthe base plate 20 is screw fastened a casing 21 of a general invertedbowl shape, this casing. 21 being provided with an opening and a flange22 extending around this opening to form a ball race for a thrust ballbearing. To the top of the casing 21 is fastened an upstanding member 23many 7 suitable manner as by bolts, said member having a forwardlyextending portion provided with an opening to serve as a bearing whichis in alignment with the flange Pivotally supported in the bearingprovided in this upstanding member 23 is a shaft 24 provided with aflanged collar 25 resting on balls 26 to form a thrust ball bearing. I

To the lower end of the shaft 24 is fastened a crank 27 by a pin 28. Tothe top end of the shaft24 is fastened an enlarged portion 29 by a pin30. This enlarged por- 1 tion is provided with a saw slotin which isfastened the spring switch member 31 by pins 32. Under normalconditions, this switch member is distorted by bearing againststationary contacts which have been conventionally illustrated by thearrows33 and 34, this switch member 31 being biased and 34 by the spiralspring 35 fastened to the shaft 24by the headed pin 36, and havingitsother end fastened by a pin 37 to a sup- 2 port extending from thecasing 21. To the hm 40 by the key 41. This balancewheel 40 ispreferably constructed of non-magnetic material, 'and has screw fastenedto the periphery thereof an armature 42 ofgeneral U- shape having itsends tapered as more clear- 1y shown in Fig. 3. The balance wheel 40 ispreferably perfectly balanced in any wellknown manner after the armature'42 has been fastened thereto. y

Supported from the casing 21 by any suitable means (not shown) is anelectro-magnet, which will for convenience be called a time startingmagnet and designated ,SC, and comprises a back yoke 45 having extendinglegs 46 terminating in enlarged pole pieces 47 constructed of agoodgrade of'magnetic material. The pole pieces .47 are pointed-on oneendand provided with an outwardly extending heel at the other end, as moreThe legs 46 of the electro-magnet are each provided with acoil48.-"-Tl1is holding or starting magnet ,jSC is normally energized tohold the armature 42against the heels of switch blade 31, to start thebalance wheel 40 in rotation. The inertia of the balance wheel 40 willcarry the spring switch blade 31 beyond the position to which it isbiased and to the dotted position, where it will engage stationarycontacts conventionally illustrated by arrows 50 and 51. The Spiralspring 35 will at this time be tensioned in the opposite direction,thereby swinging the balance wheel 40 back to Within a small distance ofits original position against the heels of the pole pieces 47. If thestarting electro-magnet SC is again energized at the time the wheel 40returns nearly to its former initial position, said electro-magnet willattract the armature 42, by flux emanating from the pointed extensionsof the pole pieces :Ttoward the pointed extensions of the armature toits original position, as illustrated in Figs. 2 and Another element ordevice of the car-car ried apparatus of this invention comprises a resetdevice. The primary function of this reset device is to restore the partof the car equipment changed from normal as a result ofa brakeapplication due to excessive speed. In the particular arrangement shown,this resetting, device comprises a shaft 52 suitably journaled in thebase plate. 20 and provided with an extending arm 53 and a knobfAoutside of the casing for facilitating rotation of said shaft. Aswitch member55 is fastened to the extension 53 but insulated therefromby insulation 56. This switch member 55- is arranged to engagestationary insulated contacts, shown conventionally as arrows, in twoextreme positions.

This reset device may be called upon to perform two functions, first,closure of said circuits by movement of the switch member 55, andsecond, rotation of the balance wheel 40 back to its normal orinitialcondition.

The first function is accomplished by turn-- ing the knob 54 in thecounter-ciockwise direction as viewed from the top, to move the switchblade 55 from the position shown to a diametrically opposite positioninto engagement with three stationary contacts. A. second function isperformed by the engagement of the extending arm 53 with the downwardextending pin of the crank 27, the parts beingso proportioned andarranged that movement of the shaft 52 to its other extreme or operatedposition will carry with it the crank 27 and the balance wheel 40. ifthese are displaced from the normal position. back to the normalposition.

In. order that this reset device may not he carelessly or maliciouslyfastened or left in its operated position, and thus prevent the properoperation of thesystem, both by interfering with the movement of thebaiance "wheel as, and by maintaining certain cir train proceed, thereset device including switch member 55 .must be restored to and left111 the normal position shown.

Operation of Figs. 1 and 2.-Let usessume that the car-carried apparatusis in its normal condition shown,that is, is on a car moving betweencontrol points in a block when the next block in advance thereof isclear. Under these conditions, the control relay CR is energized througha stick circuit which may be traced as follows:beginning at one terminalB- of a suitable source of energy, such as a battery, Wire 60, frontcontact 61 of the control relay OR, wires 62 and 63, winding of thecontrol relay CR, wire 6%, secondary coil S of the car element L, wire65 back to the common return wire C which is connected to the other sideof said source of energy.

\Vith this control relay GR in its energized. condition, a stick circuitfor-the repeater relay ER is completed which may be traced as follows:beginning at the terminal B of a battery, wire 66, front contact 67 ofthe control relay CR'wires 68 and '69, front contact 70 of the repeaterrelay RR, wires 71 and 72, winding of the repeater relay RR, wire 73back tothe common return wire C.

The energization of the control relay CR also energizes a stick circuitfor the stop relay SR which may be traced as follows beginning at theterminal B of a battery, wire 60, front contact 61 of the control re layCR, wires Hand 75, front contactxiti of the stop relay SR, wires 77 and8, Windthe common return wire C. The stick circuit for the stop relay SRjust traced is also adapted to receive current from a source of energythrough a circuit which may be traced as follows :beginning at theterminal B of a battery, stationary contact 323, spring switch member31, stationary contact 34-, wires 80 and through the rest of the stickcircuit of the stop relay SR as heretofore traced back to the'conunonreturn wire C.

l/Vith the repeater relay ltlt in its energized condition, an energizingcircuit for the starting magnet SC may be traced as follows :-beginningat the terminal 18 of a battery, wire 81, front contact 82 oftherepeater reiay RR, wire 83, coils 48 of the starting magnet SiCm'ir 84cback to the common return wire C.

With the stop reiay in its energized 111g of the stop relay SR, Wire 79back to SR, wire 87, Winding of the train control common return wire C.

device K, wire 88, stationary contact 57, movable contact 55 of thereset device, stationary contact 58, wire 89, primary coil P of the carelement L. wire 90 back to the 'The energization of the rimary coil Pproduces a inagneto-motiveorce in the core of the car element L, whichis in the same direction but greatly predominates themagneto-motive-force produced by the secondary coil S which is connectedin the energizing circuit of the control relay, CR. This is due to thefact that the current flowing through the control relay GR is verysmall, that is, this current is just sufficient to maintain the controlrelay'CR in its energized condition.- The magneto-motive-force producedby the primary and secondary coils, although being in the samedirection, produces very little flux linking both of these coils, thisbeing due to the large gap between the pole pieces 16.

With the car-carried apparatus in its normal condition, as justdescribed, let us assumethat the vehicle equipped therewith is enteringthe block I when the block J is occupied. lVith the block J occupied,the track relay 4 will be shunted by'th'e wheels and axles of the trainin block J, therebydropping the front contact 11 and deenergizing therepeater track relays 8 to open-circuit the coils 7 of the trackelements i.

As the car element passes over the first track element T, the reluctancethrough thecore 15 of the car element is'momentarily reduced. This chane in reluctance causes a sudden increase of flux through the second: arycoil S, and then a decrease to its normal condition, partly due to adiwrsion of flux from leakage paths and partly due to an increase in thetotal flux through the )rimary coil P. This sudden increase and recreateof flux through the secondary coil S induces a Volta e therein similarto that of a single cycle 0 alternating current E. M. F. The secondarywinding S is preferably so connected with respect to the battery thatthe first wave of the unicycle of E. M. F. opposes that. of the battery,thereby reducing the energizing current flowing in the winding of thecontrol relay CR to an extent to drop its'armature by the action of thespring 91. Since the control relay GR is connected in a stick circuit,it will be permanently de- .;-cnergized until picked up by some other isnot interrupted, because this stick circuit is energized through-thecircuit heretofore traced through the spring switch blade 31. Thedeenergization of the control relay CR does, however, interrupt thestick circuit for the repeater relay RR, thereby causing it to drop itsarmature and deenergize the starting magnet SC. Simultaneously with thedeenergization of the starting magnet SC, the repeater relay RR closes acircuit for picking up the control relay CR which may e traced asfollows :-beginning at the terminal B of a battery, stationary contact33, spring switch member 31 (which has not yet broken its contact withthe stationary contacts 33 and 34), wires 80 and 93, back contact 94 ofthe repeater relay RR, wires 95 and 63, winding of the control relay CR,wire 64, secondary coil S of the car ele-- ment L, wire 65 back to thecommon return wire C, thereby again energizing the control relay CRthrough its stick circuit heretofore traced.

The deenergization oi the starting mag-- net SC allows the spiral spring35 to start the balance wheel 40 upon its cycle of operatlon. litshould, however, be noted that the control relay CRbecomes again enerized,

' 31 in its extreme position, stationary contact 51, wires 97, 98 and72, winding of the repeaterv nelay RR-, wire 73 back to the commonreturn Wire C, thereby again energiziug the repeater relay RR throughits sti'ckcircuit heretofore tracedJ The energization of the repeaterrelay RR again closes its front contact 82, thereby energizing thestarting magnet SC.

As the spiral spring 35 which is now-torsioned in the opposite directionswings the balance wheel 40, in the counter-clockwise direction (asviewed from above) back to: wards'itsnormal position shown, the armature42 will be swung into the influence of the magnetism of the startingmagnet SC, and will again be attracted to its normal position incont-act with the heels of the pole pieces l7. l

Darin thiscycle of operation'of the time control device TC abovedescribed, the stop relay SR will not be deenergized, because thecontrol relay CR will be picked up before the stick circuit of the stoprelay SR through the spring switch member 31 is interrupted. Therefore,the train control assumed that the train did not reach the track elementt before the time control device had completed its operating cycle.

Let us assume now that the train passes over the track element T, andthereby deenergizes the control relay CR which deenergizes the repeaterrelay RR, thereby starting the time control device and causing the backcontact 94 to again close the pickup circuit for the control relay CR,as here-' tofore explained, without interrupting the stick circuit forthe stop relay SR. If now the car element L passes over the second trackelement It before the operating cycle of thetime control device TC hasbeen completed, the control relay CR will again be deenergized; andsince the auxiliary stick circuit for the stop relay SR is not yet againcompleted by the spring switch member 31, the stop relay SR will bedeenergized, thereby dropping its front contact 76 and inter 'ruptingits stick circuit permanently The deenergization of the stop relay SRalso causes it to drop its front contact 86, thereby deenergizing thetrain control device K and the primary coil P of the car element L. Thedeenergization of the train control device K will apply the brakes inany suitable.

manner as heretofore mentioned, thereby bringing the train to a stop. Itis noted here'that the primary coil P is connected in series with thetrain control device K. This has been done so that the interruption ofthe circuit through the primary coil P,

due to circuit failure or reduction in cur-.

rent therein below the safe value, will also deenergize the traincontrol device K, there- "by stopping the train.

. 'The train now having been brought to a stop, in order to againproceed, it will be necessary for the engineer to turn the knob 54 ofthe resetting device. If desired, this time control device TC may be solocated on the tender or the like, that it will only be accessible fromthe ground, thereby requirin the train to be brought to a stop beforethis resetting device may be operated. If the engineer now operates theresetting de vice by turning the knob 5410 the right and in thecounter-clockwise direction (as viewed from above), the contact member55 will bridge the stationary contacts 100, 101 and 102 respectively,thereby completing pick-up circuits for the repeater relay RR and thestop relay SR.

- The pick-up circuit for the repeater relay R'R-may be traced asfollows z-beginning at the terminal B of a battery, wire 105, stationarycontact 102, contact member 55, stationary contact 100, wires 106, 98and 72,

winding of the repeater relay RR, wire 7 3 back to the common returnwire C.

The pick-up circuit for the stop relay SR may be traced as follows:beginning a-tithe terminal B of a battery, wire 105, stationary contact102, contact member 55, stationary contact 101, wires 107 and 78,winding of the stop relay SB, wire 79 back to the com mon return wire Cfar enough for the switch arm 31to close both sets of its contacts, andalso come within the range of influenze of the holding or startingmagnet SC, the relays CR- and RR will be automatically re-energized andthe balance wheel returned and held in the normal position. Suchautomatic restoration may not, however, occur under unfavorableconditions; and consequently provision is made whereby manipulation ofthe reset device may be used to restore the relays CR and RR, as well asrelay SR, or the balance wheel, or all.

When the reset device is operated, as just explained, it will benotedthat the spring switch member 31 will come into contact with thestationary contacts 33 and 2-34 before the pick-up circuits for relaysRR and SR are completed, thus completing a pickup circuit for thecontrol relay CR through this spring switch blade 31 which has al-vready beentraced heretofore and includes the back contact 94 of therepeater relay RR. Relay CR, when once picked up, is stuck up throughits own stick contact 61. When switch arm55 engages contacts 100-102.The pick-up circuit for relay RR, above traced" is closed, and as soonas relay RR is picked up it is stuck through its front contact '70 andfront contact 67 of relay (11. With relay RR energized, its contact 82is closed 'to. energize the holding magnet SC to hold the balance wheel.If the balance wheel does'not return toward its normal po- (in which itis shown) to complete a circuit Lil between stationary contacts 57 and58 for this train control device.

Let us assume now that a train equipped with the apparatus illustratedin Fig. 2, and with this apparatus in its normal condi- 'tion as shown,is passing through the block ment L passes over the track element Tduring the movement of the train, as just explained, the time controldevice TC and its I coacting apparatus will perform the same cycle ofoperation as heretofore explained. As the car element L asses over thetrack element t, no effect will be produced on the car apparatusregardless of whether the speed is hi h or low because the control relayCR wil not be actuated by this track element. Although a very slightchange. of flux will take place through the secondary coil S as the carelement passes over the track element t with its coil closed in acircuit of'low resistance, this slight change of flux will induceinsufficient voltage to actuate the control relay CR, by bucking thevoltage of the battery energizing this relay, and therefore will notactuate the same. This slight change of flux is accounted for by thefact that the initial change of flux through the track element causes arelatively large current to set up in the coil 7. i This current, bywell-known laws of elec fro-magnetic induction, will be in a directiontooppose the flux producing it. Since only a slight'change of flux takesplace through the secondary coil S under these conditions, the controlrelay CR will be .maintained energized, and the car-carried devices willnot be influenced when passing over -a track element having its coilclosed in a circuit of low resistance.

From the foregoing it will be seen that i the brakes of a car may beautomatically applied at a selected control point along the track in theevent that the car is then exceeding some arbitrary speed limitcorresponding to the spacing of the track elements at that controlpoint. Obviously, the spacing of the track elements at successivecontrol points may be decreased, thereby allowing the train to travel ashorter distance at each successive point in a predetermined interval oftime, and in this manner bring the train to a low speed .at the end ofthe block.

In Fig. 4 has been illustrated a train control system which in manyrespects employs the same apparatus as does the. system shown in Figs. 1and 2, but this system is of more fied contacts.

way is provided with trackwayelements to enforce both recognition andobedience to such a caution signal.

The traekway equipment shown in Fig. 4 is in certain'respects the sameas that shown in Fig. 1, and therefore like parts have been given thesame reference characters. One outstanding distinctive feature of thistrackway system consists of an additional track element which isconstructed substantially the same as the other track elements for thepurpose of enforcing recognition or acknowledgment of a caution ordanger signal, and will for convenience be designated TA. Thisacknowledging track element TA is provided with a coil 7', which isnormallv closed in a circuit of low resistance by the front contact of adistant relay D. This distant relay D'is energized from the line wire 9and through a front contact 110 of the track relay 4. In this embodimentof the invention, the first track element T of each pair is providedwith a coil 111 which is controlled by a front contact 112 of therepeater track relay 8. Although only one pair of track elements havebeen illustrated, it is proposed that a plurality of control points willbe employed for enforcing successive decreasing speed limitssubstantially as shown in Fig.

The car-carried apparatus illustrated in Fig. 4 employs substantiallythe same devices as shown in Fig. 2, and-consequently like parts havebeen given the .same reference characters. The relays CR, RR and SR arethe same but are provided with modi- The relays CR. RR and SR areprovided with tension coil springs 130.

131 and 132 respectively for operating the movable contacts to theiropen position when these relays are deenergized.

The time control device TC, which has been conventionally shown, issubstantially the same as the time control device shown in Fig. 2, theonly distinction being that the nal, that is, in order for him to giveevidence that he has recognized this signal and realizes that it is nota clear signal. This device, for convenience called an acknowledgingdevice and designated AD, comprises an operating rod 116 slidably'supported in supports 117 and 118. The operating rod 116 is providedwith a knob 119, and has a compression coil spring 120 inserted betweenthis knob and the support 117. The operating rod 116 is provided with aninsulating pin 121 adapted to close the movable contact 122 when theknob 119 is depressed, and is provided with another insulating pin 123which is adapted to allow the spring 124 to pull the movable contact 125downward against the opposition of the dashpot 126 when the knob 119 isdepressed. The movable contact 125 is resilient and does not breakconnection with the stationary contact 127 until the hook 128engages theend thereof. lt will thus be noted that when the operating knob 119 isdepressed the movable contact 12:2 will immediately close a circuit,

whereas the movable contact 125 will not interrupt a circuit until aftera predetermined i' .terral of time depending on the retarding ability ofthe dash-pot- 126. Although any other type of retarding device, or timeelement device may be employed for postponmg the time of opening of thecircuit, the dash-pot 126 has been shown to conventionally illustratesuch a time element device.

Operation of Fig. 4.-With a car equipped with the car apparatusillustrated in Fig. d, and moving along the track under clear traflicconditions, the apparatus will be in the normal condition asillustrated. llnder this condition, the control relay CR Wlll beenergized through a stick circuit including its own front contact, whichmay be traced as tollows:--beginning at the terminal B of a suitablesource of energy, such as a battery, wire 133, front contact 134i of thecontrol relay CR, wires 135 and 136, winding ofthe control relay CR,wire 137, secondary coil 5 of the car element L. wire 138 back to thecommon return wire 0 connected to the other terminal of said source ofenergy.

The energization of the control relay CR closes a circuit for energizingthe repeater relay RR, which be traced as follows beginning at theterminal B of a battery. wire 133, front contact 13% oil? the controlrelay CR, wire 139, winding or" the repeater relay RR, wire 140- back tothe common return wire C.

With the repeater relay RR in its energized position, a circuit will beclosed for energizing the starting magnet SC, which may be traced asfollowskfbeginning at the terminal B of a battery. wire 1 11. winding ofthe starting magnet SC, wire 142. front contact 143 of the repeaterrelay; RR. wire v 144 back to the common return wire C.

With the repeater relay HR in its energized osition, a stick circuit forthe stop relay SR will also be completed. This stick circuit maybetraced as follows :beginning at the terminal 18 of a battery, wire 145,front contact 146 of the stop relay SR, wires 147 and 148, winding ofthe stop relay Slit,

teasers SR, wire 151, stationary contact 127 of the 1 acknowledgingdevice All), movable contact 125 of this device, wire 152, contacts 58,and 57 of the release device, wire 153. winding of the train controldevice K, wire 1.54. primary coil P of the car element L. wire 155 backto the common return wire C.

Assume now that a train equipped with the apparatus illustrated in Fig.l in its nor mal condition is moving in the block H, and is just aboutto enter the block Twhen either of the blocks T or J is occupied byanother train. lit is readily seen from th drawing that the distantrelay D will be deenergized it either of the. blocks l or J is occupied.With the distant relay deene'rgizcd, the coil if of the acknowledgingtrack element TA will be. open circuited, thereby making this trackelement efiective to transmit an influence to the control relay CR.

Assuming that the engineer does not notice that the signal Z at theentrance of the block I is at caution or danger, as the case may be, andpasses over the acknowledging track element TA, the passage of the carelement L over this track element TA causes the armature of the controlrelay (lit to drop 51 by the action of, the spring 130, therebydeenergizing the repeater relay RE which in turn deenergizes the stoprelay and the starting magnet SG, as is readily apparentfrom thedrawing. 11s the time control dev ce TC starts on its cycle ofoperation, a pick-up circuit for the control relay CR will be completed,which may be traced as follows beginning at the terminal B of a battcry,w re 160, stationary contact 114, contact segment 113 on the balancewheel 10, stationary contact 115, wires 1G1 and 136, winding of thecontrol relay CR, wire 13?, secondary coil S of the car element L, wire138 back to the common return wire (1 The momentary energization of thecontrol relay GR through this pick-up circuit causes it to close itsfront contacts, thereby again. completing its stick circuit heretoforetraced.

The energization of this control relay CR again energiies therepeaterrelay ldlit which in turn energizes the starting magnet SC, sothat as the balance wheel 40 completes its cycle of operation it willagain be stopped in its normal position by the action of the startingmagnet SC. The energization of the repeater relay Blit will, however,not reenergize the stop relay SR, because the dropping of this stoprelay has interrupted its stick up circuit at the contacts 146, and

. connection with Fig. 2.

ea ers therefore this stop relay SR will be permanently dcenergizcd,thereby breaking the energizing circuit for the train control device K,and applying the brakes in substantially the same manner as heretoforeexplained in This function of the train control device K will bring thetrain to astop, the engineer being unable to operate the reset device,because this reset device is only accessible from the ground, or islocked in a box, the key of which is held by some other person, such asthe conductor of a train.

The train having now been brought to a stop, and proceeding on theassumption that the reset device is only accessible from the ground, theengineer may operate the knob 54 of the resetdevice to close a pick-upcircuit for the stop relay SR, which may be traced as follows :beginningat the ter minal B of a battery, wire 162, stationary contact 102,switch member 55, contact 100 of the reset device, wires 163 and 148,winding of the stop relay SR, wires 149 and 150, front contact 143 ofthe repeater relay RR,

wire 144 back to the common return wire C.-

This pick-up circuit just traced will energize the stop relay SR,whereby its front contact 146 will be closed to complete the stickcircuit for this relay, as heretofore traced. The energization of thisstop relay SR will. however, not energize the train control device Kuntil the operating knob 54 of the reset device will be returned to itsnormal position to complete the circuit for the train control device Kthrough contacts 55, 57 and 58. It is thus seen that if the train passeseither into a caution or danger block without acknowledgement of theengineer that he has observed he has passed a signal which does notindicate clear. by the operation of the acknowledging device AD, thatthe brakes of the train will be applied in a manner unpreventable by theengineer, thereby requiring the train to be brought to I a stop afterwhich the train control apparatus may be reset to its normal conditionby the engineer from the ground, and in this manner penalizing theengineer for not observing or recognizing such a caution or.

danger signal. i

Let us assume now that the train is entering the block I under either ofthe same trafli'c conditions (caution or danger) and that the engineeris operating the ackn0wledging device AD at the time that the carelement L passes over the acknowledging track element TA. As the carelement L passes over the acknowledging track element T A, the controlrelay CR will be actuated, thereby interrupting its stick circuit andalso the energizing circuit for the repeater relay BR. Thedeenergization of the re peater relay RR deenergizes the starting magnetSC, thereby allowing the time control device TC to start upon its cycleof operation.

It should be noted at this time that the deenergization of the repeaterrelay RR does not deenergize the stop relay SR, because this stoprelayis energized through a circuit which may be traced as follows:--Beginning at the terminal B of a battery, wire 145, front contact 146of the stop relay SR, wires 147 and 148, winding of the stop relay SR,wires 149 and 165, normally open contact 122 of the acknowledging deviceAD, wire 166, stationary contact 34, movable spring contact 31,stationary contact 33 of the time control device TC, wire 167 back tothe common return wire C. The first increment of movement of the timecontrol device TC completes a pickup circuit for the control relay CRthrough the contact 113 as heretofore traced, thus causing the controlrelay CR to complete its own stick circuit and again be permanentlyenergized. The ener-.

'gization of the control relay CR again energizes the repeater relay RR,which in turn again energizes the starting magnet SC, and also completesthe main stick circuit for the stop relay SR heretofore traced.

. It should be noted that the control relay CR and repeater'relay RRwill again be picked up, as just explained, before the cirlitlll Let usassume now that'the train in question is moving through the block Iwhenthe block J is occupied by another train. Under this condition, thetrack elements T and t will have their coils open-circuited because thetrack relay 4 will be denergized, thereby deenergizing the repeatertrack relays 8 which will drop their armatures 14 and 112, therebyopening the circuits through the coil 7 of these track elements.

As the car element L passes over the first track element T, assumingthat the engineer is aware that he is in a caution block'and isoperating the acknowledging device, the car apparatus will be actuatedthrough the same and cycle of operation as occurred when the trainpassed over the acknowledging track element TA, as just explained. Ifnow the train has reduced its speed sufliciently so that it will notreach the second track element t until the time control device hascompleted its cycle, and has again completed the circuit through thespring switch blade 31 and the contact 122 of the acknowledging deviceAD, this same cycle of operation will be repeated when the train passesthe track element t, and the brakes will not be applied providing theengineer has operated the acknowledgingdevice AD.

Let us assume now that the train has passed over the first track elementT under caution trailic conditions. The engineer operating hisacknowledging device Al), the

time control device will be started on its cycle of operation, therebypicking up the control relay CR which will energize the repeater relayBR, as heretofore explained. Assuming further that at this time thetrain is exceeding the speed limit enforced by the spacing of theparticular track element in question, and that it passes over the secondtrack element t before the time control device has completed thatportion of its cycle through which the spring switch member 31 is not incontact with the stationary contacts 33 and 34, the deenergization ofthe control relay CR at this time, due to the passage of the car elementL over the track element t, interrupts the energizing circuit for therepeater relay RR which in turn deenergizes the stop relay SR, becausethe auxiliary circuit for this stop relay SR through the normally opencontact 122 of the acknowledging device AD is now open at the springswitch member 31. The deenergization of the stop relay SR will open theenergizing circuit for the train control device K, and apply thebrakessubstantially in the same manner as heretofore described, theengineer being required to reset the relay SR and train control device Kfrom the ground before he can again proceed.

It should be noted that if the engineer attempts to defeat the purposeof the acknowledging device AD by tying it down or maintaining theoperating knob 119 in its lower position in any other way, that thetrain control device K will be deenergized after an interval of timedepending on the time element device illustrated'as a daslrpot 126. Thetime element device of the ac.- knowledging device AD may be adjusted toallow sufficient time, so that the engineer need not acknowledge eachelement but that a. pair of elements may be passed by a single actuationof this device.

It is thus seen that the train control sys tem disclosed in Fig. 4 maybe used to en force'recognition of a danger or caution signal byproviding an acknowledging track element TA just before the entrance toa block; that this system may be used for enforcing obedience to acaution signal by providing pairs of track elements in a blockcontrolled by-the next block in advance which are spaced to enforcedecreasing speed limits at successive points in the block in thedirection of trailic to bring the train to a low speed. of, say, tenmiles per hour before entering the next or danger block; and that thissystem may be used by providing both types of. track elements to enforceboth obedience and recognition of a caution signal. This latter featuremaybe desirable in very long blocks where a caution signal should beacknowledged upon the entrance to the'block, but the speed may not berequired to be reduced until the train has passed a considerabledistance into. such block. A

The present invention may be readily applied to enforce reduction inspeed at the approach to sections along the trackway which arepermanently hazardous, such as, approaches to curves, down grades,drawbridges, interlocked territory. and the like. This may be done byproviding pairs of permanently active track elements, such as theelement '1 shown in Figs. 1 and 2 of the drawings, at suitable pointsback of such point of hazard. If car apparatus such as shown in Fig. 4is used, it will be necessary for the engineer to do both, acknowledgethe passage of such elements and reduce the speed inaccordancetherewith, in order to avoid an automatic brake application.

In order. to give the engineer the proper information in regard to thespeed reduction necessary, suitable permanently effective markers may beprovided, either in the form of a sign board or an illuminated marker.Similarly, suitable marker lights may be provided at traffic controlledcontrol points to inform the engineer whether he is in a caution or aclear block, what speed limit will be enforced at this control pointunder caution traffic conditions, or both, such marker lights beingpreferably controlled by the repeater relay 8 located at the particularcontrol point.

In practicing the invention shown in Fig. a, certain portions of thetrackway, for instance, such as a branch road used mostly for freightcarrying purposes, may be provided with an acknowledging track elementonly which may be considered a sufficient: safeguard for this inferiortrafl'ic territory; Whereas other portions may be provided with spacedpairs of elements to enforce predetermined permissive speed limits.

lln certain other territory, especially territory employing long blocks,it may be desirable to provide an acknowledging element just before theentrance to a block, and provide speed enforcing pairs of elements atlater points in such block to afford the desired safety, thereby givingthe full protection afforded by the system shown in Fig. 4 as hasalready been described in detail.

vcntion, there have been shown and described several typieal embodimentsthereof which have been selected more with the view 0t facilitatingexplanation of the invention, than for the purposes-of disclosing thespecific structure and arrangement of parts and circuits preferablyemployed in practice; and it should be understood that variousadaptations, modifications and addi tions may be made to this particulardisclosure without departing from the invention. For example, it iscontemplated that the system may be used in conjunction with anysuitable or well-known type of block signal system, using either director alternating current in its track circuits, and that various forms ofmechanism for controlling the application of the brakes and the supplyof propelling power may be used and governed in the same way as thetrain control device K, such brake control mechanism being of coursedesigned to effect an automatic brake. application that can not beforestalled or prevented by the engineer, and in a manner conformingwith recog nized air-brake practice.

Other deviations from the specific disclosure will be evident to thoseskilled in the art, and I desire to have it understood that the specificstructure shown and described is merely illustrative of the invention,and

does not exhaust the various embodiments thereof.

What I claim is 1. A train control system of the type in which the trainwill be automatically re-' tarded if it traversesa predetermineddistance in less than a predetermined time, in-

' eluding a time controlled device having a cycle of operation the timeof which depends on the mass of an oscillatable moving part and theaccelerating force of a spring acting to accelerate the mass first inone direction and then in the other. 1

2. Atrain control system of the type inwhich the train will beautomatically re-' tarded if it traverses a predetermined distance inlessthan a predetermined time, 1n-

eluding a time controlled device having a cycle of operation requiringsaidpredetermined time in which a mass is acted upon by a spring 'so asto be accelerated andthen deeelerated in one direction, and is thenaccelerated and decelerated back in the other direction toits normalposition;

3. A train control system of the type in which the train will beautomatically retard'ed tance in'l'essthan a predetermined time,including aetime controlled device having a cycle of operation in whicha mass-is accelerated and then decelerated in one direction, and is thenaccelerated and decelerated back; in the other direction to its normalpesiti'on, and meansfor controlling traverses a predetermined distrolledbysaid time controlled device during each cycle of operation thereof.

4. Car apparatus for train control systems comprising, influencereceiving means, a brake control apparatus, a normally energized stickrelay for controlling said apparatus, and means for dropping said stickrelay when two successive control influences are received in less than apredetermined time, said last mentioned means including a time elementdevice having a cycle of operation dependent on the period ofoscillation of a pivotally supported biased weight.

5. Car apparatus for train control systenis comprising, influencereceiving means, a brake control apparatus, and means for actuating saidbrake control apparatus when two successive control influences arereceived in less than a predetermined time, said means including a timecontrolled device having a mass held in one position and biased toanother position, whereby re leasing of said mass causes it toaccelerate,

and then decelerate in one direction and then accelerate and againdecelerate in the other direction and return substantially to its normalposition after the expiration ofa predetermined period of time.

6.- Car apparatus for train control systems comprising, a control relayconnected in a stick circuit, means actuated fromthe trackway forgoverning said control relay, a time controlled device employing thebalance wheel principle for interrupting a circuit.

tuating said brake. control apparatus when two successive controlinfluences are received in less than a predetermined time, said meansincluding a time controlled device having a mass held in one position.and biased to another position, whereby releasing of said mass causesit to accelerate and then decelerate in one direct-ion and thenaccelerate and again decelerate in the other di rection and returnsubstantially to its nor mal position after the expiration ofapredetermined period of time, and separate means for restoring saiddevice to its normal position in the event it comes to rest in thebiased position.

8. A train control system of the type in which the train will -beautomatically retarded if it traverses a predetermined distance in lessthan a predetermined time, including a time controlled device havin anormal biased position, means for, resetting said device back to saidnormal position when it has changed to its biased position,

means is in its operative position.

9. Car-carried apparatus for train control vsystems, the combination ofa brake control apparatus actuated when two successive controlinfluences are received from the trackway in less than a predeterminedtime measured by a time element device, said time element devicecomprising a mass having a normal position and held there by a mag neticfield, means for biasing said mass to a neutral position, and means forcontrolling said magnetic field to allow said mass to move beyond itsbiased neutral position and then back into said magnetic field.

10. Car-carried apparatus for train control systems, the combination'ota brake control apparatus actuated when two successive controlinfluences are received from the trackway. in less than a predeterminedtime measured by a time element device, said time element device beingof the balance wheel type in which the balance wheel is held in a biasedposition and is released upon the reception of a control influence andis again held in such biased position after the expiration of apredetermined period of tlme.

11. In a train control system, the combination of a plurality of pairsof track elements which comprise inert magnetic bodies when in theiractive stopping condition, and devices on the vehicle adapted to receiveinfluence from said track elements, and automatic means including a timeelement device of the balance wheel type for applying the brakes if twosuccessive influences are received in less than a predetermined time.

12. A speed control system of the character described comprising, incombination with brake control apparatus on the vehicle including a timeinterval device of the balance wheel type, of means partly on thevehicle and partly on the track and cooperating through an interveningair gap for imposing control influences on said vehicle in successiondependent on the distance of travel of said vehicle.

13. Brake control apparatus for train control systems of the characterdescribed comprising, a main control relay and a repeater relay, brakecontrol mechanism and a time controlled device of the balance wheeltype, said device cooperating to produce an automatic brake applicationif two successive operations of the control relay occur in less than apredetermined time.-

14. In anautomatic train control system, the combination of influencetransmitting devices along the traekway, influence receiving devices onthe vehicle, an acknowledging device, a brake-setting appliance, andmeans for actuating said brake-setting appliance to its active conditionif a single active influence transmitting device is passed over withoutthe actuation of said acknowledging device, or it two successive activeinfluence transmitting devices are passed over in less than apredetermined time regardless of whether said acknowledging device hasbeen operated.

15. An automatic train control system of the type in which the trainwill be automatically stopped it' it traverses a predetermined distancein less than a predetermined time comprising, trackway influencecom1nunieating devices located at successive points along the trackwayspaced so that the distance between successive elements determines thedistance the train may travel in a predetermined period of time, abrakesetting device adapted to act on the usual air brake system and applythe brakes if actuated, means for actuating said brake setting device iftwo successive active track elements are passed over in less than apredetermined time, an acknowledging device, and means for actuatingsaid brake setting device each time an active trackway device is passedby unless said acknowledging device is held in its active positionduring such passage.

16. In a train control system, the combination of a trackway systemcomprising territory having traekway equipment for enforcingpredetermined restrictions in the speed of a. train under cautiontrafiic conditions, and territory for enforcing recognition of a signalindicating caution, car-carried equipment including a brake controldevice and an acknowledging device for applying the brakes if the speedis not restricted or the signal is not acknowledged to manit'est itscondition when passing through the re'ipective territories under cautiontraflie conditions, and means for restricting the movement of the trainit said acknowledging device is continuously held in its active condition.

17. Car carried apparatus for automatic train control systems of thetype in which the speed of the train is restricted by permitting it totravel only a predetermined but variable distance in a certain intervalof time comprising, an influence receiving means, a brake settingdevice, a manually operable acknowledging device, and time controlledmeans for actuating said brake setting device if two successive controlinfluences are received from suitable trackway devices in less than apredetermined period of time, said last mentioned means including meansfor actuating said brake setting device upon the reception of a singlecontrol influence unless said acknowledging device is simultaneouslyheld in its active position.

18. Car carried apparatus for automatic train control systems of thetime-distance interval type comprising, a brake settingdevice, anormally energized stick relay formaintaining said brake setting deviceinactive, a cyclic time controlled device of the balance wheel typeadapted to maintain the stick circuit for said stick relay closed solong as this device is in its normal condition and which performs acycle of operation requiring a predetermined period of time wheninitiated after which it again reaches its normal inactive position, anormally energized control relay normally maintaining an auxiliary stickcircuit for said stick relay closed and maintaining said time controlleddevice in its normal dormant condition which is momentarily deenergizedupon the reception of a control influence from the trackway, whereby thereception of a single control influence causes the time controlleddevice to perform a cycle of operation during which time it is incapableof maintaining the stick circuit for the stick relay elated during whichcycle said stick relay ismaintained energized by said control relay andwhereby if two control influences are received in less than a certainperiod of time the reception of the second control influence causesdeenergization of said relay and initiation of said brake settingdevice.

19. Car carried apparatus for automatic train control systems of thetime-distance interval type comprising, a normally energized stickdevice which if deenergized causes an automatic brake application byacting on the usual air brake system, a

normally energized control relaywhich When.

inits normal condition completes a stick circuit for said stick deviceand which assumes a deenergized position momentarily upon the receptionof a control influence from the trackway, a time controlled device ofthe balance wheel type normally maintained in its inactive condition bysaid control relay and which when in said normal condition completes astick circuit'for said stick device and which if deenergized performs acycle of operation requiring a definite period of time by reason of theacceleration and deceleration of a mass, whereby the reception of asingle control influence initiates said time controlled device upon itscycle of operation and the reception of a second control influencebefore the time element device returns to normal causes deenergizationof said stick device.

20. Car-carried apparatus for train control systems including a cyclictime clement device and suitable control relays therefor, of anelectro-responsive device connected in a stick circuit for controllingthe brakes of the vehicle, means for interrupting said stick circuit bya single operation of said relays, means tor manually preventing suchinterruption, and means for interrupting said stick circuit if twosuccessive operations off-said relays occur in less than a predeterminedtime which interruption can not be prevented by operation of said lastmentioned means.

21. Car carried apparatus for automatic train control systems of thetype in which the brakes are applied if two succe;sive controlinfluences are received in less than a predetermined period of timecomprising, a normally inactive brake setting device superimposed on theusual air brake system which if actuated causes an automatic applicationof the usual air brakes, a manually operable acknowledging device, andmeans including a time controlled device for causing actuation of saidbrake setting device upon the reception of a single control influencefrom the trackway unless said acknowledging device is held in its activeposition and for actuating said brake setting device regardless ofwhether or not said acknowledging device is held in its active positionif two successive control influences are received from the trackway inless than a predetermined period of time.

22. Car carried apparatus for automatic train control systems of thetime-distance interval type comprising, a normally energized stickcontrol relay adapted to be deenergized upon reception of a momentarycontrol influence transmitted from the trackway, a normally energizedrepeater stick relay having a stick circuit including a front contact ofsaid control relay and which if deenergized completes a pick up circuitfor said control relay, a normally energized stick brake control devicehaving astick circuit including a front contact of said control relaywhich if deenergized causes an automatic brake application by actingupon the'usual air brake system, a time element device of the balancewheel type which is held in its normal position by a circuit including afront contact of said repeater relay and in this position maintains anauxiliary stick circuit for said brake control device closed and whichwhen initiated upon a cycle oi operation by deenergization of saidrepeater relay again closes a pick up circuit for said repeater stickrelay, whereby the reception of a single control influence from thetrackway causes the relays and time element device to perform a cycle oisequential operations and the reception of two'control influences inless than a pre determined period of time causes deen'ergization of saidbrake control device because both the stick circuit and the auxiliarystick circuit for said device are simultaneously broken.

23. Car carried apparatus for train controlsystems, the'combination of abrake control apparatus actuated when two suecessive control influencesare received from the trackway in less than a predetermined timemeasured by a time element device, said time element device comprising-apivotally supported balance wheel biased to a mentary deenergization ofsaid electro 10 certain intermediate position by a spring, an magnetcauses said balance Wheel to comelectro-magnet acting on an armatureasplete one cycle of oscillation after WhlCh 1t sociated with saidbalance Wheel normally is again attracted to its normal position byholding said balance Wheel in one extreme said electro-magnet. positionagainst the bias of said spring, and In testimony whereof I hereby aflixmy 15 contacts opened and closed in a certain sesignature.

allence by oscillation of said balance Wheel,

e various parts being so designed that 1110- CHARLES S. BUSHNELL.

